Forming a shoe component with rocker bottom

ABSTRACT

A method of forming a shoe component for an individual is provided and includes defining a footprint of the shoe component for the individual with an orientation relative to a rocker bottom of sheets that each have the rocker bottom and various thicknesses, selecting, from among the sheets, a sheet having a thickness appropriate for the individual based on the orientation of the footprint and removing a portion from the selected sheet reflective of a shape and size of a profile of the footprint.

BACKGROUND

Aspects of the present invention are directed to methods of forming a shoe component with a rocker bottom.

Therapeutic footwear often refers to shoes having a midsole with a rocker bottom shape. A midsole is a component of a sole of a shoe and generally provides a portion of the support provided by the sole as a whole. A midsole having a rocker bottom is typically a midsole that is partially flat proximate to the wearer's heel curved around the ball of the foot and tapered toward the toe. This shape encourages the wearer to walk in a safe manner and, if the wearer is injured or has foot problems, allows the wearer to heel and remain mobile at the same time.

Generally, midsole components having a rocker bottom are formed on a case by case basis. This means that they are each ground down from a master sheet to have a generally unique predefined shape and size. Usually, this shape and size is dictated by, for example, a recommendation of a chiropodist and/or a prescription from a podiatrist or some other medical professional.

A problem exists, however, in that the time and effort to grind down the master sheet into each midsole component such that the midsole component matches the recommendation is significant and expensive. As such, the cost of footwear including these components is also expensive and, thus, it may be difficult for those with therapeutic needs to purchase them.

SUMMARY

In accordance with an aspect of the invention, a method of forming a shoe component for an individual is provided and includes defining a footprint of the shoe component for the individual with an orientation relative to a rocker bottom of sheets that each have the rocker bottom and various thicknesses, selecting, from among the sheets, a sheet having a thickness appropriate for the individual based on the orientation of the footprint and removing a portion from the selected sheet reflective of a shape and size of a profile of the footprint.

In accordance with another aspect of the invention, a method of forming a shoe component for an individual is provided and includes determining a need of the individual for a therapeutic shoe component, evaluating a height profile of the individual, defining a footprint of the shoe component for the individual with an orientation based on the determined need relative to a rocker bottom of sheets each having the rocker bottom and various thicknesses, selecting, from among the sheets, a sheet having a thickness in accordance with the height profile and the foot print orientation and removing a portion from the selected sheet reflective of a shape and size of a profile of the footprint.

In accordance with yet another aspect of the invention, A system by which an article to be worn by an individual is formed, the system comprising a set of sheets from a selected one of which a portion is removable, the portion being reflective of a shape and size of a profile of a footprint of the individual. The sheets have various thicknesses and each sheet comprises a body including a relatively flat face and a face defining a rocker bottom opposing the relatively flat face.

BRIEF DESCRIPTIONS OF THE SEVERAL VIEWS OF THE DRAWINGS

The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other aspects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side view of sheets that each have a rocker bottom and various thicknesses;

FIG. 2 is an axial view of one of the sheets of FIG. 1;

FIG. 3 is a side view of sheets that have a rocker bottom and include a plurality of layers. The layers can be disposed upon one another;

FIG. 4 is a top view of the sheet of FIGS. 1 and 2;

FIG. 5 is a schematic illustration of a method of forming a shoe incorporating a portion of the sheet of FIGS. 1 and 2.

DETAILED DESCRIPTION

In accordance with aspects of the invention, midsole components can be formed from master sheets of midsole material that are designed with a preformed rocker bottom such that the rocker bottom of any one particular midsole component need not be ground down on an ad hoc basis. In this way, the time and effort required to manufacture footwear such as therapeutic shoes can be reduced with the costs associated with purchasing such footwear likewise reduced.

With reference to FIGS. 1-4, sheets 10, 11 and 12 are provided such that one can be chosen from which the midsole component is removable. The sheets each have a rocker bottom 10 a that is similarly shaped and a unique thickness. For example, sheet 10 has a thickness T₁, sheet 11 has a thickness T₂ and sheet 12 has a thickness T₃, where T₁<T₂<T₃. The similarities between the rocker bottoms 10 a and the differences in the thicknesses of each of the sheets 10, 11 and 12 allows the midsole components to be customizable for any individual without a need for the rocker bottom 10 a to be reformed for each sheet.

Sheet 10, as a representative example, includes a volumetric body 20 having a bottom face 21, along which the rocker bottom 10 a is defined, and a relatively flat top face 22 disposed generally in opposition to the bottom face 21. The body 20 further includes a heel portion 23 and a nose portion 24. The rocker bottom 10 a may take various forms but is generally flat proximate to the heel portion 23, curved at a mid-section and angled with respect to the relatively flat top face 22 proximate to the nose portion 24. With this construction, the sheet 10 includes a relatively rectangular heel section 15 proximate to the heel portion 23, a mid-section 16 where the rocker bottom 10 a curves and a tapered nose section 17 proximate to the nose portion 24.

The ratio of the thickness of the sheet at the heel portion 23 to the thickness at the nose portion 24 can be about 1.5:1 to about 5:1.

In one aspect as reflected in FIG. 3, the sheet 10 may be multilayered or multi-sectioned, having two or more layers or sections that are disposed upon one another or against one another. The layers may contact one another. As seen in the FIG. 3, the sheet 10 may comprise a plurality of layers 40, 42 and 44 or sections 40, 42 and 44. The layers/sections may include the same or different material compositions and may have similar or different physical characteristics (e.g., elastic modulus, shock absorption, impact strength) that can be tailored for individual comfort. For example, layer/section 40 can have different properties from that of layer 42 and 44. One or more of the layers/sections can include a foam.

A midsole component to be worn by an individual as part of a shoe can be cut from the sheet 10 to include a portion of the rocker bottom 10 a at a particular longitudinal position relative to the individual's foot and with a particular attitude such that the rocker bottom 10 a has an orientation that comports with the individual's needs. Also, the sheet from which the midsole component is cut may be chosen based on the individual's height profile. Thus, for an individual having feet of the same size that require a rocker bottom midsole of the same orientation but who has a 1 inch longer left leg, the midsole component cut for his left foot will be cut from a thicker sheet than the sheet from which the right foot midsole component is cut from. This way, the individual's height profile can be accounted for and his midsole component requirements addressed at the same time without significantly increased manufacturing costs.

With particular reference to FIG. 4, a method of forming a shoe component for an individual includes defining a footprint 31, 32, 33 of the shoe component for the individual with an orientation relative to the rocker bottom 10 a of sheets 10, 11 and 12, which, as described above, each have the rocker bottom 10 a and the various thicknesses T₁, T₂ and T₃. A particular one of the sheets is then selected due to the selected sheet having a thickness that is appropriate for the individual based on the orientation of the footprint and the individual's height profile. A portion of the selected sheet to be formable into the midsole component is then removed from the sheet and should be substantially reflective of a shape and size of a profile of the individual's footprint so that the portion can fit into the individual's footwear.

The set of sheets are formed from a variety of polymeric materials to each have the rocker bottom. The polymeric materials may contain a variety of additives, which will be listed below. The organic polymeric material can be a thermoplastic polymer, a blend of thermoplastic polymers, a thermosetting polymer, a blend of thermosetting polymers, or blends of thermoplastic polymers with thermosetting polymers. The organic polymeric material may include semi-crystalline polymers or amorphous polymers. Exemplary organic polymeric materials are elastomers. In one aspect, it is desirable for the organic polymeric material to have a tensile elastic modulus when measured at room temperature at a rate of less than or about 5 centimeters per minute of less than or equal to about 10⁷ Pascals, specifically less than or equal to about 10⁶ Pascals, and more specifically less than or equal to about 10⁵ Pascals.

As noted above, the entire sheet 10 or one or more of the layers 40, 42 or 44 can include a foam. The foam can have a porosity of about 10 to about 99 volume percent, specifically about 20 to about 80 volume percent, and more specifically about 30 to about 70 volume percent, based on the total volume of the sheet 10 or based on the total volume of the layer 40, 42 or 44. In one aspect the foam can comprise pores that have a pore size of about 100 nanometers to about 50 micrometers.

The thermoplastic polymer may include a blend of polymers, copolymers, terpolymers, or combinations including at least one of the foregoing thermoplastic polymers. The thermoplastic polymer can include an oligomer, a homopolymer, a copolymer, a block copolymer, an alternating block copolymer, a random polymer, a random copolymer, a random block copolymer, a graft copolymer, a star block copolymer, a dendrimer, or the like, or a combination comprising at last one of the foregoing thermoplastic polymers.

Examples of the thermoplastic polymers are polyacetals, polyolefins, polyacrylics, polycarbonates, polystyrenes, polyesters, polyamides, polyamideimides, polyarylates, polyarylsulfones, polyethersulfones, polyphenylene sulfides, polyvinyl chlorides, polysulfones, polyimides, polyetherimides, polytetrafluoroethylenes, polyetherketones, polyether etherketones, polyether ketone ketones, polybenzoxazoles, polyoxadiazoles, polybenzothiazinophenothiazines, polybenzothiazoles, polypyrazinoquinoxalines, polypyromellitimides, polyquinoxalines, polybenzimidazoles, polyoxindoles, polyoxoisoindolines, polydioxoisoindolines, polytriazines, polypyridazines, polypiperazines, polypyridines, polypiperidines, polytriazoles, polypyrazoles, polypyrrolidines, polycarboranes, polyoxabicyclononanes, polydibenzofurans, polyphthalides, polyacetals, polyanhydrides, polyvinyl ethers, polyvinyl thioethers, polyvinyl alcohols, polyvinyl ketones, polyvinyl halides, polyvinyl nitriles, polyvinyl esters, polysulfonates, polysulfides, polythioesters, polysulfones, polysulfonamides, polyureas, polyphosphazenes, polyphthalides, polyacetals, polyanhydrides, polyvinyl ethers, polysilazanes, polyurethanes, fluoropolymers, polysiloxanes, or the like, or a combination comprising at least one of the foregoing thermoplastic polymers.

Examples of thermosetting polymers include epoxy polymers, unsaturated polyester polymers, polyimide polymers, bismaleimide polymers, bismaleimide triazine polymers, cyanate ester polymers, vinyl polymers, benzoxazine polymers, benzocyclobutene polymers, acrylic polymers, acrylate polymers, methacrylate polymers, polyalkyds, phenol-formaldehyde polymers, novolac polymers, resole polymers, melamine-formaldehyde polymers, urea-formaldehyde polymers, polyhydroxymethylfurans, polyisocyanates, diallyl phthalate polymers, triallyl cyanurate polymers, triallyl isocyanurate polymers, unsaturated polyesterimides, polyurethanes, or the like, or a combination comprising at least one of the foregoing thermosetting polymers.

Examples of elastomers that may be used for manufacturing the sheet 10 are natural rubber, synthetic polyisoprene, butyl rubber (copolymer of isobutylene and isoprene), halogenated butyl rubbers (e.g., chloro butyl rubber, bromo butyl rubber), polybutadiene, styrene-butadiene rubber (copolymer of polystyrene and polybutadiene), nitrile rubber (copolymer of polybutadiene and acrylonitrile), also called BUNA N® rubbers, hydrogenated nitrile rubbers such as, for example, THERBAN® and ZETPOL®, carboxylated nitrile rubbers (e.g., XNBR), chloroprene rubber, such as, for example, NEOPRENE and BAYPREN, ethylene propylene rubbers (e.g., ethylene propylene rubber, a copolymer of ethylene and propylene and ethylene propylene diene rubber, a terpolymer of ethylene, propylene and a diene-component), epichlorohydrin rubber, polyacrylic rubber, silicone rubber, fluorosilicone rubber, fluoroelastomers, perfluoroelastomers, polyether block amides, chlorosulfonated polyethylene, ethylene-vinyl acetate, or the like, or a combination comprising at least one of the foregoing elastomers. An exemplary elastomer for manufacturing the sheet 10 may be polyurethane.

The sheet 10 may be manufactured by blending an organic polymer or a precursor to the organic polymer with other desired additives. Examples of such additives include anti-oxidants, anti-ozonants, anti-bacterial agents, mold release agents, reinforcing fillers (e.g., silica, titania, carbon black, carbon nanotubes, or the like), colorants, plasticizers, accelerators, vulcanization packages, inhibitors, or the like, or a combination comprising at least one of the foregoing additives. The organic polymers (or a precursor to the organic polymer) along with the additives (also known as the ingredients) may be mixed in a mixer such as a Banbury, extruder, or the like, and then molded into the desired shape.

The sheet 10 or a master sheet including a plurality of sheets 10 may be manufactured in a batch process or in a continuous process. The molding can include injection molding, compression molding, or a combination comprising at least one of the foregoing forms of molding. In an alternate embodiment, the forming may include cutting each sheet from a master sheet. Where the sheet is formed of polyurethane, it is understood that polyurethane is a 2 part liquid that is mixed and cast into open mold. The mold then closes and an exothermic reaction takes place to form sheet 10.

The orientation of the footprint relative to the rocker bottom 10 a is based on a shape of a foot of the individual. That is, if one individual's foot requires the rocker bottom 10 a to be ahead of the ball of his foot and another requires the rocker bottom 10 a to be at the ball of the foot, the footprints of each can be cut from the shame type of sheets at different longitudinal positions. Thus, as shown in FIG. 4, the first individual's footprint could be represented by footprint 31 and the second's by footprint 33. Meanwhile, a third individual's foot could require that the footprint be forward and askew such that the rocker bottom 10 a is angled relative to his foot. In this case, he might require footprint 32 to be cut from the sheet.

As mentioned above, the selecting may include determining a required thickness for the sheet to correct a disparity in leg lengths of the individual. That is, once a footprint is defined, a sheet thickness can be determined. Here, a similar footprint for each foot of an individual can be cut from respective sheets, but, if the individual's left leg is longer than his right leg, the sheet for his right foot will be thicker than that of his left foot. By the same token, if an individual has equal leg lengths and one foot requiring a forward rocker bottom and another foot requiring a rear rocker bottom, the respective footprints for each foot can be cut from sheets having similar rocker bottoms. Here, the sheets will need different thicknesses to account for the different positions of the footprint so that the individual's leg length can remain aligned with one another.

The footprint 31, 32 or 33 can be removed from the sheet by at least one of a manual operation, a machine assisted operation and automatic machining Once the footprint 31, 32 or 33 is removed from the sheet, the footprint can be shaved down in at least one of a thickness and a width direction to properly fit the footprint to the size and shape of the foot and to allow the footprint to fit within the individual's footwear.

As shown in FIG. 5, a shoe for an individual including the midsole component formed as described above can be provided. First, a need of the individual for the shoe component to have a particular shape and size is determined and a height profile of the individual is evaluated. The footprint of the shoe component for the individual is then defined in the sheet 10 with an orientation based on the determined need relative to the rocker bottom 10 a. A particular sheet is then selected as having a thickness in accordance with the height profile and the footprint orientation. A portion is removed from the selected sheet reflective of a shape and size of a profile of the footprint.

The determined need describes at least one of a shape of a foot of the individual, a gait of the individual and an injury of the individual and may be provided in a written description 40 authored by a foot professional.

Once the footprint 32 is cut, a sole 50 can be formed with additional sole layers 51 and 52 added onto the footprint 32 provided they do not adversely impact the shape of the rocker bottom 10 a. The sole 50 can then be affixed to a shoe 60 having an upper portion 61 wearable by the individual.

While the disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular exemplary embodiment disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims. 

1. A method of forming a shoe component for an individual, the method comprising: defining a footprint of the shoe component for the individual with an orientation relative to a rocker bottom of sheets that each have the rocker bottom and various thicknesses; selecting, from among the sheets, a sheet having a thickness appropriate for the individual based on the orientation of the footprint; and removing a portion from the selected sheet reflective of a shape and size of a profile of the footprint.
 2. The method according to claim 1, further comprising forming the set of sheets to each have the rocker bottom and various thicknesses.
 3. The method according to claim 1, further comprising mixing ingredients for the sheet in a mixer and molding the ingredients to form a sheet.
 4. The method according to claim 3, wherein the molding comprises injection molding.
 5. The method according to claim 1, wherein the forming comprises cutting each sheet from a master sheet.
 6. The method according to claim 1, wherein the orientation is based on a shape of a foot of the individual.
 7. The method according to claim 6, wherein the orientation longitudinally locates the rocker bottom relative to the foot.
 8. The method according to claim 6, wherein the orientation angles the rocker bottom relative to the foot.
 9. The method according to claim 1, wherein the selecting comprises determining a required thickness for the sheet to correct a disparity in leg lengths of the individual.
 10. The method according to claim 1, further wherein the removing comprises shaving the footprint in at least one of a thickness and a width direction.
 11. The method according to claim 1, wherein the removing is accomplished by at least one of a manual operation, a machine assisted operation and automatic machining
 12. A method of forming a shoe component for an individual, the method comprising: determining a need of the individual for a therapeutic shoe component; evaluating a height profile of the individual; defining a footprint of the shoe component for the individual with an orientation based on the determined need relative to a rocker bottom of sheets each having the rocker bottom and various thicknesses; selecting, from among the sheets, a sheet having a thickness in accordance with the height profile and the foot print orientation; and removing a portion from the selected sheet reflective of a shape and size of a profile of the footprint.
 13. The method according to claim 12, wherein the determined need describes at least one of a shape of a foot of the individual, a gait of the individual and an injury of the individual.
 14. The method according to claim 12, wherein the determined need is provided in a written description authored by a foot professional.
 15. The method according to claim 12, wherein the height profile describes a discrepancy between leg lengths of the individual.
 16. A system by which an article to be worn by an individual is formed, the system comprising a set of sheets from a selected one of which a portion is removable, the portion being reflective of a shape and size of a profile of a footprint of the individual, wherein: the sheets have various thicknesses, and each sheet comprises a body including a relatively flat face and a face defining a rocker bottom opposing the relatively flat face.
 17. The system according to claim 16, wherein the rocker bottom is curved and tapered toward a nose portion.
 18. The system according to claim 16, wherein each sheet has a shape and size that is larger than the footprint of the individual.
 19. The system according to claim 16, wherein the rocker bottom of each sheet has a substantially similar shape.
 20. The system according to claim 16, where each sheet comprises one or more layers.
 21. The system according to claim 16, where each sheet comprises an organic polymeric material.
 22. The system according to claim 16, where each sheet comprises natural rubber, synthetic polyisoprene, butyl rubber, halogenated butyl rubbers, polybutadiene, styrene-butadiene rubber, nitrile rubber, hydrogenated nitrile rubbers, carboxylated nitrile rubber, chloroprene rubber, ethylene propylene rubbers, ethylene propylene diene rubber, epichlorohydrin rubber, polyacrylic rubber, silicone rubber, fluorosilicone rubber, fluoroelastomers, perfluoroelastomers, polyether block amides, chlorosulfonated polyethylene, ethylene-vinyl acetate, polyurethane or a combination thereof.
 23. The system according to claim 16, further comprising an operator employed machining device to cut and/or shave the portion of the chosen sheet.
 24. The system according to claim 16, further comprising an automatic machining device to cut and/or shave the portion of the chosen sheet. 